Anisotropic microstrain broadening of minium, Pb₃O₄, in a high-pressure cell: interpretation of line-width parameters in terms of stress variations

The diffraction-line broadening exhibited by three different Pb₃O₄ phases was studied at ambient and elevated pressures. The broadening indicates strongly anisotropic microstrain, which was interpreted in terms of (local) stress variations in association with strongly anisotropic elastic properties. In particular, making use of the anisotropic compressibility of Pb₃O₄ determined on the basis of the present data, the pressure fluctuations in the employed diamond anvil cell due to non-hydrostatic conditions of the sample were estimated.